Ok so setup: -I got 39-48 front wheel cylinders on my 1932 ford roadster. They are currently 1.25x1. From speedway so of course one leaks after about a year… -1 inch master cylinder, dual reservoir, drum/drum . -4:1 pedal ratio, no brake booster -3/16 brake line leaves master, goes into residual valve Then along driver side of frame, to front driver side near wheel, T’s off and 1 short side goes to driver side wheel, other side runs past radiator to p***enger wheel. Problem: My driver side wheel cylinder is leaking. I don’t know if it has so much pressure and it’s causing the wheel cylinder caps to get crooked inside cylinder and leak or what. I took wheel off and made sure caps were straight once and it was ok for a few drives till leaking again. Potential solution: I bought Dorman wheel cylinders to try and get away from speedway but only size close enough I could find was w8264 and w8265 which are 1.375x1 and fit later model 48-50 style fords. Question: Can I use these for my setup? Do I have to replace both of them or can I replace the driver side since it appears it has higher pressure at that T due to shorter run?
pressures are the same no matter how short of a run one side has. wheel cylinders need to be the same . just get rebuild kits for your speedway cylinders. they probably just used cheap cups
I remember buying rebuilding kit but I honestly can’t remember if I installed or just straightened out my original ones… haha I know I didn’t using sand paper on the inside to clean it up like I read somewhere, I could always try that too
A lot of new wheel cylinders for early Fords have the inlet hole drilled wrong (probably Chinese junk parts), so the fluid can leak past the lip of the inner cup if it’s pushed in too far. Best bet is to have the shoe side adjusters cranked all the way out when you put the shoes on. Then you won’t push the cups in and make it leak past the cup. Do fine adjustments until the drum will finally fit over the shoes. Sounds like a lot of work, but it worked for me. If you ever want to put new cups in a used cylinder, you need to clean it up with a brake cylinder hone. Not sandpaper.
Yeah now that you mention that I remember reading that and I also remember fighting spring to get on and thinking: this is pushing in drum to far into cylinders…. if I can’t get them to stop leaking what are people’s thoughts on replacing both with 1.375 cylinders? Would that work with my setup? Better or worse braking?
I would not mismatch wheel cylinders, I think you would have it pulling to one side. The other thing is your pedal ratio is 4 to1 and no booster will give you a hard pedal. Not the cause of the leak but one more problem, maybe.
When I was doing some 40 brakes, 20 years ago, I couldn’t find the 40 cylinders so I used 48 cylinders with the bigger front half. Worked fine. I don’t know what you are buying if your supplier says they fit 48-50?
Buy a couple of cylinder kits, and a wheel cylinder hone. Lube the cups with brake fluid before you install them, if you put the cups in dry, they tend to leak more.
All good stuff in replies, here. To endorse with a recap. Pressure is pressure, a larger cylinder will deliver more force and screw-up yout steering control. Balance is mandatory. Used dirty cylinders must receive a wet honing session to produce a uniform sleeve surface. Any irregularity will fail. Sandpaper cannot deliver the surface required for a good fluid seal. Be sure that cylinder walls and cylinder cups both are wet upon re-***embly.
used to be able to buy new rubber kits for wheel cylinders- inner seals and outers. Can you still get that?
Ford changed to the larger cylinders for a good reason; to improve braking and it makes sense to use the larger cylinders. Normal replacement early Ford front cylinders are all 1-3/8" on the big end now-a-days. Seems the only '40 style 1-1/4" wheel cylinders available are Speedway's stainless sleeved wheel cylinders. There is a problem with the inlet drilling on the replacement wheel cylinders and care must be taken on the installation as mentioned in @alchemy earlier post. From what I've seen, it seems to me that all the wheel cylinders, no matter who's label is on them come from the same Chinese factory. We also found that by milling the slot on the cylinder's front piston 1/8" deeper alleviates the the problem caused by the incorrectly drilled hole (careful use of a cut-off wheel works if you don't have access to a mill). I wonder if Speedway's sleeved cylinders started out as the same incorrectly drilled cylinder casting before being sleeved and may account for the problems you have had with the front cup. Ford 3/4 & 1 ton trucks continued to use Lockheed brakes until mid '51; guess that is why the step-bore cylinders are listed beyond the '48 cut-off for p*** cars & '47 for 1/2 ton pick-ups.
I recall reading on Fordbarn that there were some early Ford wheel cylinders (ff shore) that had the internal hole drilled in the wrong place.
You may have a wheel cylinder that is incorrectly manufactured (off shore). This was discussed on Fordbarn. Look here: The Ford Barn - Search Results and here 1948 ford wheel cylinder ford - Search
Bigger wheel cylinders will make the pedal easier to push, but with more travel. Also better braking.
Thanks for all the info. Sorry been sick the last few days. I got some reading to do on those links. I’ll try first the honing. And yes I used rubber grease when I installed first time not brake fluid. @RICH B what do you mean by milling the front? Any photos? Maybe it’s just the cold meds but I don’t get it
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